The simultaneous measurement of the intensity and polarization of impact radiation

Describes a method for the simultaneous measurement of the intensity (corrected for anisotropy of emission) and the polarization of impact radiation. The method involves passing the light through a rotatable wave plate and a polarizing filter set at a certain angle. The effect of the choice of this angle and of the phase retardation of the plate is discussed. A halfwave plate is the most effective, but any retardation can be used. The effect of imperfection of the polarizing filter is also considered and expressions are developed which enable the average emitted flux and the polarization to be found from the observations. It is shown that setting the polarizer axis at 45 degrees to the direction of the exciting beam leads to considerable simplification. Simple analogue circuits which enable the corrections to be made automatically and show a representative result are described.